Capacitor energy storage feature to make U.S. October debut on light rail transit system

Remember back on May 1 when I wrote about capacitor energy storage capability in an electric passenger rail application? Described in the “CATS: ‘Contactless,’ energy-storage features give transit an edge,” was the MITRAC system from Bombardier. In this case, it is the Siemens Sitras Energy Storage system that is to be installed on the TriMet light rail line at the Tacoma substation in southeast Portland, Oregon, on TriMet’s Portland-to-Milwaukie extension. Sitras SES is due to make an October debut.

This is not the first Sitras SES application. It was noted in the press release: “Siemens Installing First Regenerative Energy Storage Unit in the U.S. on New TriMet Light Rail Line,” that, “The Sitras SES has been successfully installed in Spain and Germany, reducing the energy demand at Cologne [Germany] Transit Authority substation by 15,000 kWh [kilowatt-hours] in one month. The use of just a single energy storage unit could save a maximum of 500,000 kWh per year. In addition to the cost saving, the storage unit can reduce CO2 emissions by 300 tons per year with this reduction in energy generation.”

It was only a matter of time before this type of system found application in the U.S.

As a state-of-the-art technology, from an energy savings standpoint, it’s practical. In the area of voltage stabilization SES is practical there too.

The way the system works is, “In energy savings mode, the energy storage unit absorbs the energy generated by braking rail vehicles and stores it until the system can safely feed it back to the power supply during vehicle acceleration. As a voltage stabilizer, the energy content is constantly kept at a high level and energy is discharged when the system voltage falls below a specified limit. Installation of the Sitras Energy Storage Unit also allows TriMet to avoid placing a utility-connected substation in the same location,” as explained in the news release.

The Portland-to-Milwaukie light rail extension is slated to first go into operation in 2015. With the addition of the extension the Portland MAX system will grow to 60 miles in all and offer light rail transit service to patrons at 97 online stations, according to the release.